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Tunable white-light emission from Pr3+/Dy3+ co-doped B2O3 - TeO2 PbO - ZnO Li2O - Na2O glasses
摘要： In this paper, structural and optical analysis of boro-tellurite based glasses co-doped with Dy3+ and Pr3+ ions has been carried out. The glasses were fabricated by traditional melt quenching technique. XRD results confirm the amorphous-like nature of the glasses. FTIR spectroscopy was applied to explore the functional groups and interactions for the samples. The transition temperatures of glasses were identified by TGA/DSC analysis. Optical absorption and emission spectra of all the glasses have been recorded in the UVe Vis- NIR spectral range. Tauc's method was applied to determine the direct and indirect optical band gaps. Luminescence spectra show intense emission bands at ～482 nm and ～574 nm wavelengths under λexc = 388 nm corresponding to Dy3+: 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions. Decay time data revealed the occurrence of a non-radiative energy transfer from Dy3+ to Pr3+ ions. Intense emission bands are identified at ～602 nm (orange), ～487 nm (blue) and ～574 nm (yellow) observed upon λexc = 437 nm, corresponding to Pr3+:1D2→3H4, Pr3+:3P0,1,2 → 3H4/Dy3+: 4F9/2 → 6H13/2 and Dy3+: 4F9/2 → 6H13/2 transitions, respectively, where the Dy3+ emissions are due to energy transfer from Pr3+ to Dy3+ ions. The CIE chromaticity results confirm that different colors can be generated by tuning the exciting wavelength, where all the glasses are capable to emit white light under λexc = 388 nm, while at λexc = 437 nm the samples (S2eS4) emit reddish orange light. Accordingly, it is plausible to suggest these glasses for white LED and SSL applications.
关键词： Optical absorption,Photoluminescence,W-LEDs,Raman spectroscopy,Borotellurite glass,Energy transfer
更新于2025-09-23 15:23:52
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An fluorescent aptasensor for sensitive detection of tumor marker based on the FRET of a sandwich structured QDs-AFP-AuNPs
摘要： The detection of alpha-fetoprotein (AFP) is of great importance for hepatocellular carcinoma (HCC) diagnosis, but it needs to be further improved because of poor sensitivity and complicated operating steps. In this paper, a simple and sensitive homogeneous aptasensor for AFP has been developed based on F?rster resonance energy transfer (FRET) where the AFP aptamer labeled luminescent CdTe quantum dots (QDs) as a donor and anti-AFP antibody functional gold nanoparticles (AuNPs) as an acceptor. In the presence of AFP, the bio-affinity between aptamer, target, and antibody made the QDs and AuNPs close enough, thus the fluorescence of CdTe QDs quenched though the FRET between QD and AuNP. The fluorescent aptasensor for AFP showed a concentration-dependent decrease of fluorescence intensity in the low nanomolar range and a detecting linear range of 0.5-45 ng mL?1, with a detection limit of 400 pg mL?1. Moreover, this homogeneous aptasensor is simple and reliable, and obtained satisfying results for the detection of AFP in human serum samples. With more and more aptamers for biomarkers have been selected gradually, this approach could be easily extended to detection of a wide range of biomarkers. The proposed aptasensor has great potential for carcinoma screening in point-of-care testing and even in field use.
关键词： alpha fetoprotein (AFP),fluorescent aptasensor,biomarker,hepatocellular carcinoma,F?rster resonance energy transfer (FRET)
更新于2025-09-23 15:23:52
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Lignosulfonate: a Convenient FRET Platform for the Construction of Ratiometric Fluorescence pH-Sensing Probe
摘要： Lignin is a kind of natural fluorescent polymer material. However, the application based on the fluorescent property of lignin was rarely reported. Herein, a non-covalent lignin-based Fluorescence Resonance Energy Transfer (FRET) system was readily constructed by physical blending method with spirolactam Rhodamine B (SRhB) and lignosulfonate (LS) as the acceptor and donor groups, respectively. The FRET behavior, self-assembly and energy transfer mechanism of SRhB/LS composite were systematically studied. It was demonstrated that LS could be used as a convenient aptamer as energy donor to construct water-soluble ratiometric sensors because of its inherent property of intra-micelle energy transfer cascades. Our results not only presented a facile and general strategy for producing lignin-based functional material, but also provided a fundamental understanding about lignin fluorescent to promote the functional and high-valued applications of lignin fluorescence characteristic.
关键词： lignin,ratiometric sensor,FRET,intra-micelle energy transfer cascade
更新于2025-09-23 15:23:52
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Spectrally Resolved Ultrafast Exciton Transfer in Mixed Perovskite Quantum Wells
摘要： Solution-processed perovskite quantum wells have been used to fabricate increasingly efficient and stable optoelectronic devices. Little is known about the dynamics of photogenerated excitons in perovskite quantum wells within the first few hundred femtoseconds – a crucial timescale on which energy and charge transfer processes may compete. Here we use ultrafast transient absorption and two-dimensional electronic spectroscopy to clarify the movement of excitons and charges in reduced-dimensional perovskite solids. We report excitonic funneling from strongly to weakly confined perovskite quantum wells within 150 fs, facilitated by strong spectral overlap and orientational alignment among neighboring wells. This energy transfer happens on timescales orders of magnitude faster than charge transfer, which we find to occur instead over 10 - 100s of picoseconds. Simulations of both F?rster-type interwell exciton transfer and free carrier charge transfer are in agreement with these experimental findings, with theoretical exciton transfer calculated to occur in 100s of fs.
关键词： energy transfer,Carrier,metal halide perovskite,two-dimensional electronic spectroscopy,layered perovskite,dynamics
更新于2025-09-23 15:23:52
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Harnessing the synergy between upconverting nanoparticles and lanthanide complexes in a multi-wavelength responsive hybrid system
摘要： We prepared a hybrid system composed of a continuous film of dinuclear lanthanide complex [Ln2bpm(tfaa)6] (Ln = Tb or Eu) and upconverting nanoparticles (UCNPs) using a straightforward drop-cast methodology. The system displayed visible emission under near-infrared (NIR) excitation, simultaneously stemming from sub-10-nm UCNPs and [Ln2] complexes, the latter species being otherwise directly excitable only using UV-blue radiation. In light of the results of steady-state – including power-dependent – and time-resolved optical measurements, we identified the radiative, primarily ligand-mediated nature of the energy transfer from Tm3+ ions in the UCNPs-to-Ln3+ ions in the complexes. Hyperspectral mapping and electron microscopy observations of the surface of the hybrid system confirmed the continuous and concomitant distribution of UCNPs and lanthanide complexes over the extensive composite films. Key features of the hybrid system are the simultaneous UV-blue and NIR light harvesting capabilities and their ease of preparation. These traits render the presented hybrid system a formidable candidate for the development of photoactivated devices capable to operate under multiple excitation wavelength and to transduce the absorbed light into narrow, well-defined spectral regions.
关键词： hybrid system,complex,energy transfer,lanthanide,films,upconverting nanoparticles,hyperspectral imaging
更新于2025-09-23 15:23:52
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Machine Learning of Two-Dimensional Spectroscopic Data
摘要： Two-dimensional electronic spectroscopy has become one of the main experimental tools for analyzing the dynamics of excitonic energy transfer in large molecular complexes. Simplified theoretical models are usually employed to extract model parameters from the experimental spectral data. Here we show that computationally expensive but exact theoretical methods encoded into a neural network can be used to extract model parameters and infer structural information such as dipole orientation from two dimensional electronic spectra (2DES) or reversely, to produce 2DES from model parameters. We propose to use machine learning as a tool to predict unknown parameters in the models underlying recorded spectra and as a way to encode computationally expensive numerical methods into efficient prediction tools. We showcase the use of a trained neural network to efficiently compute disordered averaged spectra and demonstrate that disorder averaging has non-trivial effects for polarization controlled 2DES.
关键词： Neural Networks,excitonic energy transfer,light-harvesting complexes,ML numerical methods
更新于2025-09-23 15:23:52
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Insights into anti-thermal quenching of photoluminescence from SrCaGa4O8 based on defect state and application in temperature sensing
摘要： Herein, a self-activated phosphor SrCaGa4O8 with excellent thermal stability was synthesized by high temperature solid state reaction method. It exhibited the broad emission range from 300 to 600 nm under 220 nm excitation, which may be caused by the intrinsic defects of host. Specifically, with the temperature increasing, the photoluminescence (PL) color changed from bluish to yellow-green and the maximum of PL intensity at 550 nm was obtained when reaching 493 K. From thermoluminescence curves and high temperature spectra, it was found that the anti-thermal quenching phenomenon could be dependent on the self-compensation of the carriers. Accordingly, the results of temperature-dependent intensity ratio and sensitivity show that SrCaGa4O8 may have potential in the optical temperature sensing.
关键词： Energy transfer,Self-activated phosphor,Optical properties,Anti-thermal quenching,Sensors
更新于2025-09-23 15:22:29
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A self-illuminating nanoparticle for inflammation imaging and cancer therapy
摘要： Nanoparticles have been extensively used for inflammation imaging and photodynamic therapy of cancer. However, the major translational barriers to most nanoparticle-based imaging and therapy applications are the limited depth of tissue penetration, inevitable requirement of external irradiation, and poor biocompatibility of the nanoparticles. To overcome these critical limitations, we synthesized a sensitive, specific, biodegradable luminescent nanoparticle that is self-assembled from an amphiphilic polymeric conjugate with a luminescent donor (luminol) and a fluorescent acceptor [chlorin e6 (Ce6)] for in vivo luminescence imaging and photodynamic therapy in deep tissues. Mechanistically, reactive oxygen species (ROS) and myeloperoxidase generated in inflammatory sites or the tumor microenvironment trigger bioluminescence resonance energy transfer and the production of singlet oxygen (1O2) from the nanoparticle, enabling in vivo imaging and cancer therapy, respectively. This self-illuminating nanoparticle shows an excellent in vivo imaging capability with suitable tissue penetration and resolution in diverse animal models of inflammation. It is also proven to be a selective, potent, and safe antitumor nanomedicine that specifically kills cancer cells via in situ 1O2 produced in the tumor microenvironment, which contains a high level of ROS.
关键词： photodynamic therapy,cancer therapy,inflammation imaging,reactive oxygen species,myeloperoxidase,bioluminescence resonance energy transfer,nanoparticles
更新于2025-09-23 15:22:29
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The luminescent properties of GdAlO<SUB align="right">3:Tb<SUP align="right">3+</SUP> phosphors based on molten salts addition
摘要： The (Gd1–xTbx)AlO3 (x = 0–0.12) were obtained through ammonium bicarbonate co-precipitation technology. The pure-phase (Gd1–xTbx)AlO3 with good dispersion could be obtained at relatively lower temperature of 1,000°C. Under optimum UV excitation into 275 nm, the photoluminescence (PL) spectra display a series of 5D4–7FJ transitions of Tb3+ in (Gd1–xTbx)AlO3 system with the strongest green emission at ~546 nm. The overlapping between 8S7/2–6IJ intra f-f transition of Gd3+ and 4f8–4f75d1 transition of Tb3+ at 275 nm suggesting the Gd3+ → Tb3+ energy transfer, and the quenching contents of Tb3+ was found to be ~10 at%. The luminescent property of GdAlO3:Tb3+ phosphor could be further improved with molten salt incorporation. The optimal composition of molten salts was determined to be the mixture of NaCl/Na2SO4 (5 wt% NaCl), and the mass ratio of mixture molten salts to precursor was 2:1. The relationship between the luminescent property and molten salts composition were studied in detail.
关键词： energy transfer,GdAlO3:Tb3+ phosphor,molten salts,luminescent property
更新于2025-09-23 15:22:29
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Investigation of energy transfer in Pr3+, Yb3+ co-doped phosphate phosphor: the role of 3P0 and 1D2
摘要： The synthesis, crystal structure and photoluminescence and decay kinetics properties have been carried out for the Pr3+-Yb3+ co-doped YPO4 phosphors. Upon excitation with 447 nm, the intense emissions from 3P0, 1D2 and 1G4 excited states are all observed in the Pr3+ singly doped phosphors. The population of 1D2 state is attributed to cross-relaxation 3P0 +3H4 → 1D2+3H6 and/or non-radiative multiphonon relaxation from 3P0 because of the larger maximum phonon energy of YPO4 host (1080 cm-1),which needs only 3-4 phonons to balance the energy gap between 3P0 and 1D2 excited states. For the Pr3+-Yb3+ codoped samples, the effect of Yb3+ concentration on the luminescence and decay kinetics of Pr3+ are investigated for the interpretation of observed experimental results. The observations and discussions manifest that the efficient energy transfer from Pr3+ to Yb3+ occurs, involving mainly 1D2 and 1G4 levels of Pr3+ ions instead of 3P0 level, which is not in accordance with many reported results. It is hoped that our results may give a new insights into the energy transfer mechanism in Pr3+-Yb3+ codoped system.
关键词： YPO4,luminescence decay,emission intensity,energy transfer
更新于2025-09-23 15:22:29